1. Field of the Invention
The present invention relates to a roller levelling machine for levelling a rolled section. The machine includes a section inlet for introducing the rolled section into the roller levelling machine and a plurality of bending rollers for levelling the rolled section.
2. Description of the Related Art
Roller levelling machines of this type are disclosed, for example, in the published Brochure No. WZ/3123 "Rollenrichtmaschinen fur schwere Walzprofile und Schienen" [roller levelling machines for heavy rolled sections and rails] of SMS Schloemann-Siemag Aktiengesellschaft in Dusseldorf, Germany.
In the ideal situation, an absolutely straight section is to be produced when levelling rolled sections. However, in the practical application, the rolled section is slightly bent, i.e., the section has a radius of curvature which is large, but not infinite. Consequently, the height of the arc which a rolled section includes with a chord between the ends of the rolled section is in the first approximation proportional to the square of the length of the rolled section. However, industrial standard EN 10034 requires a linear dependency of the maximum height of the arc on the length of the rolled section. Therefore, long rolled sections must have a greater straightness than short rolled sections. This leads to substantial problems in long rolled sections.